its bending but not deforming as expected, looks like rotating around model origin

4 files changed, 28 insertions, 13 deletions

diff --git a/src/animation.c b/src/animation.c
index de7e9a2..7a79529 100644
--- a/src/animation.c
+++ b/src/animation.c
@@ -6,14 +6,14 @@ keyframe animation_sample(animation_sampler *sampler, f32 t) {
   size_t previous_index = 0;
   f32 previous_time = 0.0;
   // look forwards
-  DEBUG("%d\n", sampler->animation.values.kind);
-  TRACE("Here %d", sampler->animation.n_timestamps);
-  for (u32 i = 1; i < sampler->animation.n_timestamps; i++) {
+  // DEBUG("%d\n", sampler->animation.values.kind);
+  TRACE("Total timestamps %d", sampler->animation.n_timestamps);
+  for (u32 i = 0; i < sampler->animation.n_timestamps; i++) {
     f32 current_time = sampler->animation.timestamps[i];
     if (current_time > t) {
       break;
     }
-    previous_time = current_time;
+    previous_time = sampler->animation.timestamps[i];
     previous_index = i;
   }
 
@@ -28,7 +28,7 @@ keyframe animation_sample(animation_sampler *sampler, f32 t) {
 
   f32 time_diff =
       sampler->animation.timestamps[next_index] - sampler->animation.timestamps[previous_index];
-  f32 percent = (t - sampler->animation.timestamps[next_index]) / time_diff;
+  f32 percent = (t - previous_time) / time_diff;
 
   quat interpolated_rot =
       quat_slerp(sampler->animation.values.values[previous_index].rotation,
diff --git a/src/maths/maths.h b/src/maths/maths.h
index 76531f2..911b9b7 100644
--- a/src/maths/maths.h
+++ b/src/maths/maths.h
@@ -302,7 +302,7 @@ static inline mat4 mat4_look_at(vec3 position, vec3 target, vec3 up) {
 
 #define TRANSFORM_DEFAULT                                                 \
   ((transform){ .position = VEC3_ZERO,                                    \
-                .rotation = (quat){ .x = 0., .y = 0., .z = 0., .w = 0. }, \
+                .rotation = (quat){ .x = 0., .y = 0., .z = 0., .w = 1. }, \
                 .scale = 1.0,                                             \
                 .is_dirty = false })
 
@@ -311,8 +311,10 @@ static transform transform_create(vec3 pos, quat rot, f32 scale) {
 }
 
 static inline mat4 transform_to_mat(transform *tf) {
-  // TODO: rotation
-  return mat4_mult(mat4_translation(tf->position), mat4_scale(tf->scale));
+  mat4 scale = mat4_scale(tf->scale);
+  mat4 rotation = mat4_rotation(tf->rotation);
+  mat4 translation = mat4_translation(tf->position);
+  return mat4_mult(translation, mat4_mult(rotation, scale));
 }
 
 // --- Sizing asserts
diff --git a/src/renderer/render.c b/src/renderer/render.c
index 42f6ee4..d7e2d48 100644
--- a/src/renderer/render.c
+++ b/src/renderer/render.c
@@ -1,6 +1,7 @@
 #include <assert.h>
 #include <stdlib.h>
 #include <string.h>
+#include "animation.h"
 #include "maths_types.h"
 #include "mem.h"
 #define STB_IMAGE_IMPLEMENTATION
@@ -192,8 +193,19 @@ void draw_skinned_mesh(renderer* ren, mesh* mesh, transform tf, material* mat, m
 
   // for now assume correct ordering
   mat4* bone_transforms = malloc(n_bones * sizeof(mat4));
+  mat4 parent = mat4_ident();
   for (int bone_i = 0; bone_i < n_bones; bone_i++) {
-    bone_transforms[bone_i] = mat4_ident();
+    transform tf = mesh->bones->data[bone_i].transform_components;
+    mat4 local = transform_to_mat(&mesh->bones->data[bone_i].transform_components);
+    bone_transforms[bone_i] = mat4_mult(parent, local);
+    parent = bone_transforms[bone_i];
+  }
+
+  // premultiply the inverses
+  for (int bone_i = 0; bone_i < n_bones; bone_i++) {
+    joint j = mesh->bones->data[bone_i];
+    // bone_transforms[bone_i] = mat4_mult(bone_transforms[bone_i], j.inverse_bind_matrix);
+    bone_transforms[bone_i] = mat4_mult(bone_transforms[bone_i], j.inverse_bind_matrix);
   }
 
   glUniformMatrix4fv(glGetUniformLocation(lighting_shader.program_id, "boneMatrices"), n_bones,
diff --git a/src/resources/gltf.c b/src/resources/gltf.c
index 7efd2bb..7668a49 100644
--- a/src/resources/gltf.c
+++ b/src/resources/gltf.c
@@ -89,7 +89,7 @@ bool model_load_gltf_str(const char *file_string, const char *filepath, str8 rel
   vec4u_darray *tmp_joint_indices = vec4u_darray_new(1000);
   vec4_darray *tmp_weights = vec4_darray_new(1000);
   joint_darray *tmp_joints = joint_darray_new(256);
-  vertex_bone_data_darray* tmp_vertex_bone_data = vertex_bone_data_darray_new(1000);
+  vertex_bone_data_darray *tmp_vertex_bone_data = vertex_bone_data_darray_new(1000);
 
   cgltf_options options = { 0 };
   cgltf_data *data = NULL;
@@ -276,7 +276,7 @@ bool model_load_gltf_str(const char *file_string, const char *filepath, str8 rel
 
     mesh mesh = { 0 };
     mesh.vertices = vertex_darray_new(10);
-    mesh.vertex_bone_data =vertex_bone_data_darray_new(1);
+    mesh.vertex_bone_data = vertex_bone_data_darray_new(1);
 
     if (primitive.material != NULL) {
       for (int i = 0; i < material_darray_len(out_model->materials); i++) {
@@ -297,7 +297,8 @@ bool model_load_gltf_str(const char *file_string, const char *filepath, str8 rel
         vertex_bone_data data;
         data.joints = tmp_joint_indices->data[i];
         data.weights = tmp_weights->data[i];
-        vertex_bone_data_darray_push(tmp_vertex_bone_data, data); // Push the temp data that aligns with raw vertices
+        vertex_bone_data_darray_push(tmp_vertex_bone_data,
+                                     data);  // Push the temp data that aligns with raw vertices
       }
       for (int i = 0; i < tmp_joints->len; i++) {
         joint data = tmp_joints->data[i];
@@ -330,7 +331,7 @@ bool model_load_gltf_str(const char *file_string, const char *filepath, str8 rel
         vertex_darray_push(mesh.vertices, vert);
 
         if (is_skinned) {
-          vertex_bone_data vbd = tmp_vertex_bone_data->data[index]; // create a copy
+          vertex_bone_data vbd = tmp_vertex_bone_data->data[index];  // create a copy
           vertex_bone_data_darray_push(mesh.vertex_bone_data, vbd);
         }
         // for each vertex do the bone data